From the prior art it is known to provide the planetary carriers of planetary gearsets with rotation-resisting check-plates for the planetary gearwheels. Theoretically the planetary gearwheels and radial needle bearings are not subjected to axial forces but nevertheless, owing to deformation and tolerances or imprecision, these components drift laterally toward the planetary carrier. In the case of steel planetary gearwheels and planetary carriers the check-plates are made of bronze or brass, whose relative movement takes place either toward the planetary gearwheel or toward the planetary carrier. With planetary carriers made of aluminum, steel check-plates with phosphates surfaces are also used, the phosphate coating serving as wear protection between the check-plate and the planetary gearwheel.
It is also known, in particular with an aluminum planetary carrier, to make the check-plates of bronze or brass and fix them relative to the planetary carrier in order to avoid drifting of the check-plates toward the planetary carrier. In this way the relative rotational speed is transferred to the planetary gearwheel so that drifting of the check-plates is prevented. In such cases the check-plates are as a rule fixed relative to the planetary carrier by means of metal bent-over straps on the check-plates.
The bending of the straps as a rule produces an unsymmetrical component which, for that reason, demands precise assembly in relation to rotation about the bolt axis and in relation to the fitting direction. On the one hand, a rotationally symmetrical design of the component facilitates its positioning in the circumferential direction during assembly; on the other hand, during assembly even with such a design, attention must be paid to the fitting direction.
DE 10 2004 014 578 A1 by the present applicant describes a planetary transmission in which an inner, central gear meshes with at least one planetary gearwheel and in turn the planetary gearwheel is in meshing engagement with a ring gear, and each planetary gearwheel is mounted on a planetary bolt supported on a planetary carrier. The known planetary transmission comprises at least one check-plate associated with the planetary gearwheel, which is positioned between the planetary gearwheel and the planetary carrier and whose geometrical shape can be chosen freely. The geometrical shape is designed such that fitting of the check-plate must take place in a fixed orientation and direction, while in the event of erroneous assembly the ring gear and/or the inner, central gear cannot be fitted.
Furthermore, DE 10 2004 047 160 A1 by the present applicant describes a planetary transmission with an outer, ring gear and an inner, central gear, wherein at least one planetary gearwheel is arranged between the ring gear and the central gear and meshes with them both, and wherein each planetary gearwheel is mounted on a planetary gearwheel bolt attached by a support to a planetary carrier, the bolts having bores for the supply of lubricant. In this known transmission, a check-plate is arranged on at least one side between the planetary gearwheel and the planetary carrier, this being provided both for the planetary gearwheel and for the support and which consists of a case-hardened metallic material coated with a tungsten-carbon carbide layer. This provides durable contact surfaces which are substantially less prone to generate heat and which extend the life of the planetary gearwheel mounting. In its assembled condition the at least one check-plate can have bent-over straps.